How Sildenafil (Viagra) Works?

Sildenafil in the form of Viagra has worked like the magic blue pill for many years. Lets understand how it works. Viagra (Sildenafil), Cialis (Tadalafil) and Levitra (Vardenafil) are all PDE5 inhibitors and work by inhibiting PDE5 enzyme in the penis – now the question arises, what has PDE5 inhibition got to do with erection quality. Lets try and phrase the answer in a simple manner.

What is needed for good erections?

For good erections, the corpus cavernosum(spongy regions in the penis) should relax and that is dependent on the intracellular calcium levels which is in turn dependent on the amount of cGMP produced. The lesser calcium levels induce relaxation of the spongy tissues. Reduced calcium levels in the spongy tissues is the key point here.

What happens in men with erectile dysfunction?

In men with unsatisfactory erections, often due to certain constrictions, the helican arteries leading to the spongy tissues in the penis are not able to supply enough blood and need extended levels of spongy tissue and helican artery relaxation. Other reasons could be – the cGMP getting quickly metabolized by the PDE5 enzyme or the initial quantity of cGMP itself or perhaps inadequate production of nitric oxide due to anxiety, hormonal imbalances etc.

How Viagra, Cialis and Levitra help?

Sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra) selectively inhibit the PDE5 enzyme. This inhibition of PDE5 ensures that very little cGMP is broken down thereby causing a build up of cGMP levels.

The adequate cGMP levels ensures decrease in intracellular calcium level in the spongy corpus cavernosum which enables it to relax and receive and hold more blood which translates to better erections for longer period of time.

Selective Inhibition
Sildenafil selectively inhibits the PDE5 enzyme in the human body which is rather unique and targeted to sexual potency. The other PDE enzymes (PDE1-PDE4, PDE6-PDE12) are very mildly affected, thereby making it work the way it should work and affecting nowhere else significantly. Truly remarkable!

Arousal Dependency
It is to be noted that sildenafil by itself doesn’t cause any relaxation of the smooth muscle, instead it works by enhancing the effect of NO that is produced in the human body when a man is aroused. As such, for sildenafil to work, sexual arousal is necessary.